bug#10754: define-minor-mode and doc of derived mode

[Stefan Monnier]

>>> We can add an optional arg to `define-minor-mode'.
>> I'd rather avoid it if I can.
> I meant a keyword argument when I was saying optional.

That's what I understood, and I'd still rather avoid that.

I think we can avoid it by looking for the presence of ARG in
the docstring (or by simply always adding it, and then going through
the various minor modes and remove the corresponding text from their
docstrings).


        Stefan